American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 455
y first to ground 38o AMERICAN TELEGRAPHY. the battery in the central office. The lineman then goes to the most centrally locatedcall box and grounds the circuit at that point. This, if the trouble is an opencircuit, puts in all the call boxes on one side of his ground. He then goes to a… … SERVICE SLIP DRAWERS, The first District messenger service system was established in this country abouteighteen years ago, on a small scale. To-day it is estimated that there are over 150-000 call boxes in operation. When the service was inaugurated, a rental was chargedfor the use of the box in…
Telegraph
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
